boot: espressif: add support for upgrade modes w/o scratch

Upgrade using move decreases flash wear and is now the default mode
used by Zephyr.

The implementation is done by MCUboot itself, so it is just a matter of
setting the correct define to enable it.

Swap using move was successfully tested with ESP32C6.

Signed-off-by: Martin Jäger <martin@libre.solar>